You have 20 pounds of flour that must be distributed into 10 sacks of 2 pounds each.

At your disposal is a scale, and two weights: a 5 pound one and a 9 pound one.

How can you complete this job in only 9 weighings?

First take 9pound weight in one arm of the scale and 5pound in the other. place one sack in each arm. Fill the sack on 5kg arm with the flour till the scale balances. You have 4kgs in this sack. remove the 9 and 5 pound weights. Now remove the flour from sack and put it into the one on other arm till the scales balance. Now you have sacks weighing 2pounds of flour each in two weighings. One of these sacks can be further used for measuring 2 pounds. Repeat this procedure till 2kgs is left remaining, which does not required to be weighed, as by that time we would have filled 9 bags with 9 weighings.

Posted by Gautam on 2003-01-20 22:06:01